Advanced neointimal growth is not associated with a low risk of in-stent thrombus. Optical coherence tomographic findings after first-generation drug-eluting stent implantation.

BACKGROUND: There is a hypothesis that advanced neointimal stent coverage may protect against stent thrombosis. In the present study, differences in neointimal growth and prevalence of in-stent thrombus between paclitaxel- and sirolimus-eluting stent (PES and SES) were evaluated by optical coherence tomography (OCT). METHODS AND
RESULTS: Follow-up angiographic and OCT examinations at approximately 6 months were performed for 40 patients (20 PES, 20 SES). Late loss was measured by quantitative coronary angiography. Neointimal hyperplasia (NIH) thickness on stent struts was measured by cross-sectional OCT images at 1 mm intervals. After measuring the NIH area in each cross-section, NIH volume was calculated as integral of NIH area within the stent. Late loss, NIH thickness, and NIH volume were greater for PES than for SES (0.42 +/-0.44 vs 0.13 +/-0.12 mm, 118 +/-141 vs 31 +/-39 mum, 53.2 +/-30.5 vs 24.3 +/-14.0 mm(3); P<0.05, respectively). In-stent thrombus was found more frequently in PES than in SES (50 vs 15%; P=0.02).
CONCLUSIONS: Although the degree of neointimal growth in PES was generally greater, in-stent thrombus was more common compared with SES. Presence of thrombus in first-generation drug-eluting stents was not related to advanced neointimal growth.